Production covered in this analysis is from the Carlin and Twin Creek complexes. Combined production from these compexes is over 1Moz/a. About 80% of overall gold production is from the treatment of high-grade refractory ores and the balance mainly from heap leaching as well as conventional milling and cyanide leaching. Ore from these mines is treated according to its characteristics and is processed at either Mill 6 (higher grade refractory ores) or by conventional differential flotation milling and cyanide leaching for lower grade ore at Mill 5. A portion of the lower grade material is also heap leached. The combined operation covered in this analysis produced 1.3Moz in 2017, and is expected to produce in excess of 1Moz until at least 2021.